Accumulator with full-flow filtering

ABSTRACT

An accumulator for an air conditioning system is adapted to ensure that any fluid exiting the accumulator has been filtered. Fluid comprising gaseous refrigerant, liquid refrigerant and oil enters the accumulator. Ideally, only gaseous refrigerant and oil will exit the accumulator. According to one embodiment, gaseous refrigerant is substantially separated from liquid refrigerant. Oil is entrained within the gaseous refrigerant. The gaseous refrigerant with the entrained oil is filtered prior to exiting the accumulator. In another embodiment, gaseous refrigerant, which has been separated from the liquid refrigerant, is filtered before the oil is entrained with it. The oil is then separately filtered.

FIELD OF THE INVENTION

The invention relates to accumulators for air-conditioning systems and is particularly concerned with filters for accumulators.

BACKGROUND OF THE INVENTION

Closed-loop refrigeration systems conventionally employ a compressor that is meant to draw in gaseous refrigerant at relatively low pressure and discharge hot refrigerant at relatively high pressure. The hot refrigerant condenses into liquid as it is cooled in a condenser. A small orifice, valve, tube, or other restriction divides the system into high and low-pressure sides. The liquid on the high-pressure side passes through the restriction and expands at least partly to gas, hence the general term for the restriction is “expansion device”. Some systems operate in “transcritical” mode, in that the hot refrigerant is merely cooled in the high side heat exchanger, now termed a “gas cooler”, and turns to gas plus liquid as it passes through the expansion device. At low heat loads, it is not possible to evaporate all the liquid the compressor is capable of supplying to the evaporator. Further, excess refrigerant is typically added to the system during manufacture to compensate for unavoidable leakage during the working life of the system. However excess liquid refrigerant entering the compressor (known as “slugging”) causes system efficiency loss and can damage the compressor. Hence it is standard practice to include a reservoir, called a suction line accumulator or simply an accumulator, between the evaporator and the compressor to separate and store the excess liquid.

An accumulator is typically a metal can, welded together, and often has fittings attached for a switch, transducer and/or charge port. One or more inlet tubes and an outlet tube pierce the top, sides, or occasionally the bottom, or attach to fittings provided for that purpose. The refrigerant flowing into a typical accumulator will impinge upon a deflector or baffle intended to reduce the likelihood of liquid flowing out the exit, generally by removing kinetic energy from the liquid so it settles quietly into the reservoir area without churning or splashing. In current standard use many accumulators use a variation of a dome deflector (as shown in, for example, U.S. Pat. Nos. 4,474,035 and 4,111,005), usually because they are simplest and most cost-effective. However, there are some designs of accumulators that do not use deflectors.

Some accumulators are designed to reduce the pressure drop across the accumulator (an important system performance parameter).

Certain accumulators incorporate a desiccant. Some refrigerant systems are more susceptible to moisture ingression and damage than others, especially less modern systems. However, for most systems, it is necessary to remove any moisture. The accumulator is a convenient location to house a desiccating element. Typical modern desiccant containers for this purpose incorporate a porous fabric bag of some suitable shape, containing beads of desiccating material like alumino-silicate zeolite, and secured to some inner feature of the accumulator, such as a J-tube, for example, at a position where the beads will contact the liquid refrigerant.

A consequence of using a suction line accumulator is that compressor oil can become trapped within it. Compressor oil is circulated with the refrigerant in most systems in current usage. Even if an oil separator is used, a small amount of oil escapes into the system. This oil will find its way into the accumulator, and while liquid refrigerant may be expected to evaporate and return to circulation as needed, the oil does not evaporate. Various different designs having various tubes, shapes, and configurations have been attempted to return this oil to circulation with the minimum amount of oil inventory left in the accumulator. One design incorporates a J-shaped outlet tube, or J-tube or U-tube, to carry the exiting gaseous refrigerant from the top of the accumulator down to the bottom and then back up to an outlet from the accumulator. A carefully sized orifice or hole at the bottom of this J-tube entrains the oil from the bottom of the liquid area into the stream of exiting gas. A different style replaces the J-tube with a plastic liner (sometimes referred to as a liner-style accumulator) to effect the oil return function.

Generally the oil return hole has a coarse filter around it to prevent detritus from clogging the hole. The filter on the oil return hole may prevent large particles from returning to the compressor, but only those particles large enough to settle out of the gas stream and into the reservoir will be filtered by the coarse filter. Particles small enough to remain entrained in the gas flow during passage through the accumulator would bypass the filter on the oil return hole.

As suggested above, one of the functions of an accumulator is to separate gaseous refrigerant and oil from liquid refrigerant. The combination of structures in each type of accumulator for performing such separation may be referred to as a separator or separation means. Some specific types of separators are described herein. Sometimes a deflector and/or other means are used to separate gaseous refrigerant from both liquid refrigerant and oil. Such means may also be referred to as a separator or separator means. Many different types and designs are possible, as is known to those skilled in the art.

Further, the functions of an accumulator, such as separating fluid as described above, and possibly adsorbing moisture from some or all of the fluid, may be referred to as processing of a fluid.

As compressors in mobile air-conditioning systems are becoming more sophisticated, they are also becoming susceptible to damage from particulate matter entering the compression chambers. Hence it would be desirable to be able to achieve 100% filtration of the refrigerant. In some cases, filtration is performed by filters on the high pressure side, generally incorporated into the expansion device (ie: an orifice tube and a thermal expansion valve). However, these filters are not fine enough for current requirements, nor do they stop particles that originate between the expansion device and the compressor inlet. It would be desirable to place a filter immediately before the compressor. However it is well known that the performance of air-conditioning systems deteriorates with decreasing conductance of the lines connecting the evaporator to the compressor, that is, with increasing suction line pressure drop. Hence installing a suction line filter decreases system performance.

The pressure drop across a filter relates most strongly to the restriction in open area, due to both the area occluded by the solid components forming the matrix that provides the filter pores, and to the area occluded should the pores become clogged by detritus removed from the flow by the filter. Hence there is a need for a filter with a relatively large open area to reduce the negative impact upon system performance. As suggested above, historically, only small filters with a small open area have been installed in fittings, connections, or ports of components (for example on the compressor inlet port), because adding another, separate component to the system would cause an undesirable cost and increase complexity, especially if the component is a large filter in a canister. Accordingly, it would be desirable to have 100% filtration of the suction line that does not impede flow greatly and does not add excessive cost, complexity, or components.

SUMMARY OF THE INVENTION

According to one aspect, the invention provides an accumulator for an air conditioner or HVAC system comprising a filter for filtering substantially separated gaseous refrigerant and oil. The filter is adapted to ensure that any fluid exiting the accumulator has been filtered, without greatly impeding flow or adding excessive cost, complexity or components.

Embodiments of the invention may be used in vehicles.

According to another aspect, the invention provides an accumulator for an air conditioning system for processing a fluid, the fluid comprising gaseous refrigerant, liquid refrigerant and oil, the accumulator comprising a separator means for substantially separating the gaseous refrigerant and the oil from the liquid refrigerant, and a filter for filtering the substantially separated gaseous refrigerant and the oil, whereby the filter is adapted to ensure that all fluid exiting the accumulator has been filtered.

According to yet another aspect, the invention provides an accumulator for an air conditioning system for processing a fluid, the fluid comprising gaseous refrigerant, liquid refrigerant and oil, the accumulator comprising a separator means for substantially separating the gaseous refrigerant from remaining fluid, wherein the remaining fluid comprises oil and liquid refrigerant; a first filter for separately filtering the separated gaseous refrigerant; and a second filter for filtering the oil; wherein the first filter and the second filter ensure that all fluid exiting the accumulator has been filtered.

Different embodiments of the present invention may permit some of the following benefits:

providing filtration of 100% of the refrigerant exiting the accumulator;

providing separate filtration of gaseous refrigerant from liquid refrigerant;

providing filters which are relatively easy to secure within an accumulator;

providing filters that may be easily inserted by hand, if necessary;

overcoming a problem if a filter is used downstream from an oil bleed hole in a liner-style accumulator; historically, in such cases, particles that are removed by the filter may fall off the filter and collect around the oil bleed hole, thereby clogging the oil bleed hole; however, in certain embodiments of a liner-style accumulator described herein, particles falling from a filter located downstream from the oil bleed hole would not collect around the oil bleed hole and therefore would not prevent flow through it;

similar to the previously mentioned benefit, embodiments herein where the filter is located in an outlet tube, downstream from the oil bleed hole, may be “self-cleaning” filters; as refrigerant passes through the filter, particles are left on the underside of the filter; normal vibrations during operation may cause small particles to fall off the filter; because of the nature of the liner-style accumulator described herein, such particles would have no opportunity to plug the oil bleed hole;

providing filters that are easily manufactured;

providing filters with minimal effect on accumulator function, size, assembly, installation, cost, or complexity;

providing filters with a large surface area to provide minimal pressure drop, as flow through the filter can be distributed over the surface area of the filter.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described with reference to the attached drawings in which:

FIG. 1 is a perspective view of an accumulator according to an embodiment of the present invention;

FIG. 2 a is a vertical sectional view of FIG. 1 in accordance with an embodiment of the present invention;

FIG. 2 b is a perspective view of FIG. 2 a (with desiccant removed);

FIG. 2 c is a partially exploded, sectional view of a portion of the accumulator of FIG. 2 a;

FIG. 2 d is a magnified view of the circled portion of FIG. 2 a;

FIG. 2 e is an exploded view of a portion of the accumulator of FIG. 2 a;

FIG. 3 is a vertical sectional view of the accumulator of FIG. 1 in accordance with another embodiment of the present invention;

FIG. 4 a is a vertical sectional view of the accumulator of FIG. 1 in accordance with another embodiment of the present invention;

FIGS. 4 b and 4 c are perspective views of the filter of FIG. 4 a, with the filter right side up and right side down, respectively;

FIG. 5 a is a vertical sectional view of the accumulator of FIG. 1 in accordance with another embodiment of the present invention;

FIGS. 5 b and 5 c are perspective views of the filter of FIG. 5 a;

FIG. 6 is a vertical sectional view of the accumulator of FIG. 1 in accordance with another embodiment of the present invention;

FIG. 7 a is a vertical sectional view of the accumulator of FIG. 1 in accordance with another embodiment of the present invention;

FIG. 7 b is a view looking down on the accumulator of FIG. 7 a with the top portion removed;

FIG. 7 c is a perspective view of the deflector of FIGS. 7 a and 7 b with the filters shown above, and removed from, the chimneys (for example purposes);

FIG. 8 a is a vertical sectional view of the accumulator of FIG. 1 in accordance with another embodiment of the present invention;

FIG. 8 b is a partially exploded view of a portion of the accumulator of FIG. 8 a;

FIG. 8 c is a cross-sectional view along line 8 c-8 c of FIG. 8 a;

FIG. 8 d is a perspective view of the filter apparatus of FIG. 8 a;

FIG. 8 e is a magnified view of the circled portion of FIG. 8 c;

FIG. 9 a is a vertical sectional view of an accumulator in accordance with another embodiment of the present invention;

FIG. 9 b is a perspective view of a portion of the accumulator of FIG. 9 a;

FIG. 9 c is a cross-sectional view looking up along line 9 c-9 c of FIG. 9 a;

FIG. 10 a is an exploded view of a J-tube style accumulator, in accordance with another embodiment of the present invention;

FIG. 10 b is a partially exploded view of part of the accumulator of FIG. 10 a;

FIG. 10 c is a perspective view of the filter body separated from the cap of the accumulator of FIG. 10 a;

FIG. 10 d is a perspective view of the filter engaged over a part of the J-tube of FIG. 10 a (with a portion of the mesh screen not shown for illustration purposes);

FIG. 10 e is a perspective view of the assembled accumulator of FIG. 10 a, omitting the accumulator can and cap;

FIG. 11 a is a perspective view of a reverse flow liner-style accumulator, in accordance with another embodiment of the present invention;

FIG. 11 b is a vertical sectional view (except for the filter body) of the accumulator of FIG. 11 a; and

FIG. 11 c is a different vertical sectional view of the accumulator of FIG. 11 a.

DETAILED DESCRIPTION

A representative accumulator 10 is shown in FIG. 1. A vertical sectional view of FIG. 1 is shown in FIG. 2 a. The accumulator 10 of FIG. 2 a is representative of a type having a liner 12. Different views of the accumulator of FIG. 2 a are shown in FIGS. 2 b-2 e.

An outer container 14 of the accumulator 10 may be referred to as a can 14. The can 14 has a generally cylindrical shape, closed on its bottom end. A top portion 16 of the accumulator 10 is hermetically sealed to the can 14. The top portion 16 as shown in FIG. 1 has an inlet opening 20 (as perhaps best seen in FIG. 2 e) and an outlet opening 22.

The liner 12 sits within the can 14. The liner 12 is generally cylindrical. The circumference of the liner 12 is generally concentric with the circumference of the can 14. A bottom portion of the liner 12 curves inward and upward, to form a generally circular stop 24 (see FIG. 2 b). The liner 12 is spaced from the can 14 by feet 26 (as shown in FIG. 2 a) and vertical spacers 30 (as shown in FIG. 2 c), thereby creating a gap 32 between the exterior of the liner 12 and the can 14.

An outlet tube 34 extends through most of the height of the liner 12.

A desiccant cup 36 is shown near the bottom of the liner 12. The desiccant cup 36 contains desiccant 38. The desiccant cup may incorporate a filter or screen (not shown) to protect the oil bleed hole from clogging. The desiccant cup 36 has a central opening 40 (perhaps best seen in FIG. 2 b) which, in this embodiment, surrounds the outlet tube 34. The desiccant cup 36 otherwise extends across the diameter of the liner 12. The desiccant cup 36 sits on the circular stop 24 of the liner 12. The outlet tube 34, as suggested above, extends through (or partially through) the opening 40 in the desiccant cup 36.

In this embodiment, an upper portion of the outlet tube 34 extends into a filter housing 42. The filter housing 42 includes an upper portion 44 and a lower portion 46. A filter 50, as will be described in greater detail below, is housed within the filter housing 42 between the upper portion 44 and the lower portion 46.

A deflector 52 is shown in FIG. 2 e. The deflector 52 incorporates an outflow opening 54 formed therein to allow fluid to exit the accumulator 10. Otherwise (as can been seen in the alternate embodiment of FIG. 7 c), the deflector 52 has a deflecting surface 56 having an apex line 60. The apex line 60 extends partway along a diameter of the deflecting surface 56. The deflecting surface 56 extends downwardly on both sides of the apex line 60 towards generally semi-circular openings 62.

As suggested above, in the embodiment of FIGS. 2 a to 2 e, the upper portion 44 of the filter housing 42 is formed by the underside of the deflector 52. (In other embodiments (not shown), the upper portion 44 of the filter housing 42 could be separate from the deflector 52.) The upper portion 44 of the filter housing 42 is generally cylindrical. A lower portion 46 of the filter housing 42 is formed as a separate element in this embodiment. The lower portion 46 has a generally circular top portion 64, extending downward to a smaller, generally circular lower opening 65. The lower opening 65 is adapted for secure engagement with the upper portion of the outlet tube 34.

There are many different ways to secure a filter within a filter housing. In this embodiment, as shown in FIG. 2 d, an outer flange 66 of the upper portion 44 of the filter housing 42 extends beyond an outer flange 70 of the lower portion 46 of the filter housing 42 to allow the filter 50 to be secured between the upper portion 44 and the lower portion 46 of the filter housing 42. In particular, the outer flange 66 of the upper portion 44 has an indentation or seat 72. A periphery 74 of the filter 50 is secured between the indentation 72 of the flange 66 of the upper portion 44 and a top surface of the flange 70 of the lower portion 46.

As suggested above, the periphery 74 of the filter 50 is snap fit between the upper portion 44 of the filter housing 42 and the lower portion 46 of the filter housing 42. However, there are an infinite number of different means possible for securing the filter 50 within a filter housing, as are well-known to those skilled in the art, including different techniques for snap fitting, gluing, ultra sonic welding, slip fitting, etc.

The filter 50, as shown in FIG. 2 e, is generally flat and circular. The filter 50 has one or more mesh screens 76, supported by a periphery 74 and supports 80. The filter 50, including the periphery 74 and the supports 80 may be made of any suitable material, including plastic or metal. The mesh screen 76 has openings small enough to filter particles that should be prevented from exiting the accumulator 10.

As noted above, the top portion of the outlet tube 34 fits within the circular lower opening 65 of the lower portion 46 of the filter housing 42. The outlet tube 34 could also be manufactured integrally with the lower portion 46 of the filter housing 42.

The deflector 52 incorporates a number of passageways or chimneys 82. Each chimney 82 has a raised liquid protection barrier 83, to prevent liquid from entering the chimney 82.

In operation, when the accumulator 10 is completely assembled, refrigerant enters the inlet opening 20 and impinges upon the deflecting surface 56 of the deflector 52. The refrigerant is directed towards one of the semi-circular openings 62 and is then directed downward, inside the liner 12. Gaseous refrigerant moves back upward, through the chimneys 82 in the deflector 52, and then travels down the gap 32 between the can 14 and the liner 12 and then flows under the bottom of the liner 12 and into the outlet tube 34.

Liquid refrigerant flows through a somewhat different path. Liquid refrigerant (which also includes oil) after passing through the semi-circular openings 62 in the deflector 52, flows down the inside of the liner 12 to the desiccant cup 36. The liquid refrigerant and oil pass through the desiccant cup 36, with moisture within the fluid being adsorbed by the desiccant 38. In general, the liquid refrigerant remains on or near the floor of the liner 12 unless it passes through an oil bleed hole (not shown). The oil, in this embodiment, flows through the oil bleed (or oil return) hole (not shown) located at or near a low point in the liner 12. The oil that flows through the oil bleed hole becomes entrained in the flow of gaseous refrigerant and is carried up the outlet tube 34 with the gaseous refrigerant. The gaseous refrigerant with the entrained oil passes through the filter 50 and then up and out the outlet opening 22. Although a small amount of liquid refrigerant may pass through the oil bleed hole, the gaseous refrigerant remains substantially separated from the liquid refrigerant.

The path through the accumulator 10 taken by fluid flowing from the oil bleed hole to the outlet opening 22 may be referred to as an outlet passage. In the embodiment of FIG. 2 a, for example, the outlet passage includes the opening 40 of the desiccant cup 36, the opening through the outlet tube 34, the openings through the filter housing 42, as well as the outflow opening 54 in the deflector 52. However, as suggested herein, there are many different ways and structures to create an outlet passage, as would be apparent to one skilled in the art, and as suggested by the other embodiments described herein.

The flow of the fluid through the accumulator 10 determines whether one element is upstream or downstream from another element. For example, the outlet tube 34 is downstream from the gap 32. The oil return hole is upstream from the outlet tube 34.

Another embodiment is shown in FIG. 3. In this embodiment, a filter 84 is secured within a housing 86 by clamping, welding, or other suitable means. The housing 86 could be integral with the outlet tube 34 or connected, in-line with it by force-fitting, welding, clamping, or other suitable means. The housing 86 secures the filter 84 in place, across the diameter of the housing 86, advantageously, where the diameter is greatest. The housing 86 preferably has a relatively large diameter, to maximize the open area of the filter 84. This embodiment is shown within a liner-style accumulator, generally similar to that shown in FIG. 2 a. A deflector is shown in FIG. 3. It functions in a manner similar to that shown and described with respect to FIG. 2 a.

Another embodiment is shown in FIG. 4 a. This embodiment shows a representative liner-style accumulator, with an outlet tube 34. A filter 90 is secured at or near a bottom portion of an outlet tube 34 by welding, clamping, or other suitable means. To maximize the filter surface area, the filter 90 is preferably located in or above a large space, where the gaseous refrigerant and entrained oil enter the outlet tube 34. The shape of the filter 90 in cross-section is a truncated cone. A mesh 92 extends across the bottom and sides of the filter 90, as suggested in the perspective views of FIGS. 4 b and 4 c. In other embodiments, the shape of the filter could be that of a cone, a dome, a pyramid, or other extrusion (not shown) to increase the open area of the filter.

Another embodiment is shown in FIG. 5 a. In this embodiment, a filter 100 is located at or near a bottom portion of the outlet tube 34. As shown in the perspective views of FIGS. 5 b and 5 c, the filter 100 has mesh screening 103. The filter 100 is cone-shaped, with the apex 102 of the cone pointing upward. The cone shape creates a relatively large surface area.

While the embodiments of FIGS. 4 a and 5 a feature filters located at or near a bottom portion of an outlet tube 34, a filter could be located at any point in the outlet tube 34. FIG. 6, for example, shows an embodiment incorporating a downward-pointing cone shaped filter 104 located at or near a top portion of an outlet tube 34.

Another embodiment is shown in FIGS. 7 a-7 c. In this embodiment, again relating to a liner-style accumulator, filters 106 are located within the chimneys 82. As described above with respect to FIG. 2 a, refrigerant enters through the inlet opening 20 and passes down through the semi-circular openings 62 in the deflector 52, to the inner portion of the liner 12. Gaseous refrigerant then exits the inner portion of the liner 12 up through the chimneys 82, and then travels down the gap 32 between the outside of the liner 12 and the inside of the can 14. As shown in FIGS. 7 b and 7 c, filters 106 are secured to the chimneys 82, so that all gaseous refrigerant flowing though them is filtered.

In this embodiment, the filters 106 are located upstream from where oil is entrained with the gaseous refrigerant. Accordingly, a separate filter (not shown) is located in or near the oil return (or oil bleed) hole (not shown) which filters the oil.

Another embodiment is shown in FIGS. 8 a-8 e. In this embodiment, a filter apparatus 110 is secured in the gap 32 between the liner 12 (or the deflector 52) and the can 14. As shown in FIG. 8 d, the filter apparatus 110 is in the form of a disc. The filter apparatus 110 has an outer, generally circular wall 112 and an inner, generally circular wall 114, concentric with the outer wall 112. A filter 116 (as shown in FIG. 8 e) extends between the outer wall 112 and the inner wall 114. Advantageously, support bars 120 extend across the filter 116, between the outer wall 112 and the inner wall 114, to support the filter 116, itself, and the filter apparatus 110 as a whole.

The deflector 52 of this embodiment, as perhaps best shown in FIG. 8 b, has a main exterior wall 122, beneath which is an indented expansion joint 124. The exterior wall 122 is connected to the expansion joint 124 through a step 126. The diameter of the expansion joint 124 is sized to fit within the diameter of an upper portion of the liner 12.

As shown in FIG. 8 b, the outer wall of the liner 12 has vertical spacers 30.

When the accumulator of the embodiment of FIG. 8 a is assembled, the filter apparatus 110 is secured, on its top and bottom surfaces, between the step 126 of the deflector 52 and a top portion of the liner 12, respectively. The filter apparatus 110 is secured on its side surfaces, between the expansion joint 124 of the deflector 52 and the inner surface of the can 14.

In operation, after the gaseous refrigerant flows through the chimneys 82 in the deflector 52, the refrigerant then flows down the gap 32 between the liner 12 (or the deflector 52) and the can 14. Accordingly, the gaseous refrigerant flows through the filter 116. In this embodiment, similar to the embodiment of FIG. 7 a, the gaseous refrigerant is filtered before encountering the oil. Therefore, the oil is filtered separately, as described above.

In the embodiment of FIG. 8 a, the filter apparatus 110 is described as being secured between the deflector 52 and the can 14. However, the filter apparatus 110 could be located at any point within the gap 32 between the liner 12 and the can 14. Of course, a different technique known to those skilled in the art would be necessary to secure the filter apparatus 110.

Another embodiment is shown in FIGS. 9 a-9 c. This embodiment relates to a different type of accumulator 130, which may be referred to as a pick-up style accumulator 130. A more detailed explanation of this style of accumulator is found in U.S. patent application No. 60/512,102, the contents of which are incorporated herein by reference.

The accumulator 130 of FIGS. 8 a-8 c incorporates a can 132 having an inlet port 134 and an outlet port 136. An outlet tube 140 is secured within or to the outlet port 136. The outlet tube has an entrance 141. A deflector 142 is secured to the outlet tube 140. The deflector 142 in this embodiment has a rounded top surface. The circumference of the deflector 142 has a diameter less than the diameter of the can 132, so that when the deflector 142 is installed, a gap 144 exists between the deflector 142 and an inner surface of the can 132.

A filter 146 is secured across an inner cross-section of the deflector 142. The filter 146 is advantageously secured at or near a bottom portion of the deflector 146, and in any event, below or upstream from the entrance 141 of the outlet tube 140. The filter 146 is generally flat, having a periphery 150 and support bars 152.

A hollow pick-up tube 154 is secured to the outlet tube 140, so that an inner passage of the pick-up tube communicates with the outlet tube 140. A hollow reservoir or filter holder 156 is secured to a lower end of the pick-up tube 154. The filter holder 156 has an inlet (not shown) having its own filter (not shown).

In operation, refrigerant and oil enter the accumulator 130 of FIG. 9 a through the inlet port 134. The refrigerant and oil are deflected off or against the top surface of the deflector 142, where the fluid is then directed towards the inner surface of the can 132 and down. The liquid refrigerant and oil flow to the bottom of the can 132. The gaseous refrigerant flows up through the filter 146 secured in the deflector 142 and then out through the outlet tube 140. Oil in the bottom of the can 132 flows through the filter (not shown) in the filter holder 156, and then up the pick-up tube 154 and is then entrained in the gaseous refrigerant flowing out the outlet tube 140.

Another embodiment is shown in FIGS. 11 a to 11 c. FIGS. 11 a to 11 c show a liner-style accumulator 200 in which the direction of gas flow is reversed from that in the accumulator 10 in FIG. 2 a, for example. The accumulator 200 has a top portion 202 and a bottom portion 204. The top portion has an inlet opening 206. The bottom portion has an outlet portion 210. Within the accumulator 200 is a liner 212, spaced from the bottom portion 204, thereby creating a gap 214. At or near the bottom of the liner 212 is an oil bleed hole (not shown). A desiccant cup 216 is secured within the liner 212. The desiccant cup 216 has a central opening. Desiccant (not shown) is trapped within the desiccant cup by the mesh screens 220. Either the mesh screens 220 or the oil bleed hole or both incorporate a filter for filtering fluid before fluid exits the oil bleed hole. A gas flow tube 222 is secured within the central opening of the desiccant cup 216. Over a top entrance of the gas flow tube 222 is a filter body 224, having a mesh screen (not shown) and other features similar to the filter body 164 described below with respect to the embodiments of FIGS. 10 a to 10 e. A deflector body 226 is secured above the filter body 224.

In operation, fluid enters the accumulator 200 through the inlet opening 206, and hits the deflector 226, which helps to separate gaseous refrigerant from liquid refrigerant and oil. The liquid refrigerant and oil are directed towards the liner 212 and then flow downward due to gravity, through the desiccant cup 216 to the bottom of the liner 212.

The gaseous refrigerant, upon separating from the liquid fluid, flows through the mesh screen of the filter body 224 and then into and down the gas flow tube 222. The gas then flows into and up the gap 214 and then out the outlet opening 210. As gaseous refrigerant flows past the oil bleed hole, oil (and perhaps some liquid refrigerant) is entrained within the flow of gas. The oil is filtered prior to exiting the oil bleed hole.

Although the embodiments described above relate to certain liner-style accumulators, the concepts described herein could also be implemented in other types of liner-style accumulators as well as non-liner-style accumulators, including J-tube (or U-tube) style accumulators, among others. In the case of J-tube-style accumulators, a filter could be located in the inlet or outlet of a J-tube. Moreover, a filter could also be located in an inlet port or outlet port of an accumulator of any style.

An embodiment of a J-tube (or U-tube) style accumulator is shown in FIGS. 10 a-10 e. FIG. 10 a is an exploded view showing an accumulator can 160, a J-tube 162, a filter body 164, a filter cap 166, a deflector 170, and a J-tube housing 172. The J-tube 162 has an inlet 174 and an outlet 176.

FIG. 10 b is a partially exploded view of the deflector 170, the filter body 164 and the J-tube 162. As shown in this view, the J-tube 162 has an oil bleed (or oil return) hole 180, advantageously located near a lower section of the J-tube 162. The oil bleed hole 180 may incorporate an oil bleed filter (not shown). In the embodiment shown in FIG. 10 a, the J-tube housing 172, when in use, wraps around the J-tube 162 (or part of the J-tube 162) and provides a filter (not shown) for liquid passing through the oil bleed hole 180. The J-tube housing 172 may also incorporate a small oil return hole (not shown) to control the oil flow more precisely. The deflector 170 has an outlet opening 182 for securely engaging the J-tube outlet 176. The deflector 170 has semi-circular openings 184. The deflector 170 also has a socket 186, for securely engaging a top portion 190 of the filter body 164.

FIG. 10 c is an exploded perspective view of the filter body 164 separated from the filter cap 166. The filter body 164 has the top portion 190, ribs 192 and a mesh screen 194, secured to the ribs 192. The mesh screen 194 may be made of nylon, steel or any other suitable material. The filter body 164 and cap 166 may be made of a plastic material, such as nylon. The cap 166 may be shear fit and ultrasonically welded to the filter body 164 for a no-leak seal. Alternatively, the cap 166 may just be ultrasonically welded to the filter body 164 for a no-leak seal. The surface on the cap 166 that mates with the filter body 164 can have a joint detail (not shown) for the ultrasonic weld. One rib 192 of the filter body 164 may be wider than the other ribs 192 to hide the seam of the mesh screen (not shown).

FIG. 10 d is a perspective view of a portion of the J-tube 162 engaged with the filter body 164. The inlet 174 of the J-tube 162 is inserted into the filter body 164 until it sits on several standoffs 196 which prevent over-insertion (or otherwise incorrect installation) of the J-tube and also prevents movement of the J-tube 162. The top 190 of the filter body 164 may be a solid section which may press up against a bottom or lower surface of the deflector 170. Alternatively, as suggested in FIG. 11 b, the top portion 190 of the filter body 164 can be held securely in a mating socket 186. If a socket is used, it may be desirable that only the solid top 190 of the filter body 164 extend into the socket 186, to prevent unwanted horizontal force being applied to the ribs 192 or the mesh screen 194. The use of a socket 186, apart from securing the J-tube 162 within the can 160 may also help ensure that the J-tube 162 is correctly oriented during assembly. The socket 186 may also help prevent rotation or movement of the J-tube 162 during assembly or operation. The location of the filter body 164, just under the deflector 170, helps prevent liquid carryover.

FIG. 10 e is a perspective view of the assembled accumulator of FIGS. 10 a-10 d without the can 160. In operation, fluid enters the accumulator and passes through the semi-circular openings 184 of the deflector 170. Gaseous refrigerant enters filter body 164 through the mesh screen 194. The cylindrical design of the filter body 164 maximizes or increases the filter area by allowing 360° of gas flow into the J-tube 162. The gaseous refrigerant then travels through the J-tube 162 and exits through the deflector outlet opening 182 and then exits the accumulator. Liquid refrigerant and oil, after passing though the semi-circular openings 184 of the deflector 170, flow to a floor of the can 160. Oil (and possibly some liquid refrigerant) will then flow through the oil bleed hole 180 in the J-tube 162, having passed through the oil bleed hole filter (not shown), to become entrained in the flow of gaseous refrigerant through the J-tube.

Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein. 

1. An accumulator for an air conditioning system for processing a fluid, the fluid comprising gaseous refrigerant, liquid refrigerant and oil, the accumulator comprising a separator means for substantially separating the gaseous refrigerant and the oil from the liquid refrigerant, and a filter for filtering the substantially separated gaseous refrigerant and the oil, whereby the filter is adapted to ensure that all fluid exiting the accumulator has been filtered.
 2. The accumulator of claim 1, wherein the accumulator is a liner-style accumulator comprising an inlet opening; an outlet opening; an accumulator can; a liner disposed within and spaced from the accumulator can; one or more passageways adapted to allow the gaseous refrigerant to flow to a gap between the liner and the can; an oil return hole in the liner; and an outlet passage positioned downstream from the oil return hole, and the outlet passage being positioned down stream from the gap, wherein the outlet passage communicates with the outlet opening; wherein the filter extends across the outlet passage.
 3. The accumulator of claim 2, wherein the outlet passage comprises an outlet tube, and the filter being positioned at or near a lower end of the outlet tube.
 4. The accumulator of claim 3, wherein the filter is generally cone shaped, and positioned pointing upward.
 5. The accumulator of claim 3, wherein the outlet passage comprises an outlet tube and the filter is positioned at or near an upper end of the outlet tube.
 6. The accumulator of claim 5, wherein the filter is generally cone shaped, and positioned pointing downward.
 7. The accumulator of claim 2, wherein the outlet passage comprises an outlet tube and a filter housing, the filter housing being positioned downstream from the outlet tube, the filter housing having a diameter greater than the diameter of the outlet tube and the filter extending across a cross-section of the filter housing.
 8. The accumulator of claim 7, wherein the accumulator further comprises a deflector positioned downstream from the inlet opening, the deflector having an upper portion and a lower portion, the upper portion of the deflector being adapted to deflect the fluid entering the accumulator through the inlet opening and the lower portion comprising at least a part of the filter housing.
 9. The accumulator of claim 8, wherein the filter housing comprises a first portion and a second portion, the first portion being the lower portion of the deflector, and the second portion being positioned between the outlet tube and the first portion, and the filter being secured between the first portion and the second portion.
 10. An accumulator for an air conditioning system for processing a fluid, the fluid comprising gaseous refrigerant, liquid refrigerant and oil, the accumulator comprising a separator means for substantially separating the gaseous refrigerant from remaining fluid, wherein the remaining fluid comprises oil and liquid refrigerant; a first filter for separately filtering the separated gaseous refrigerant; and a second filter for filtering the oil; wherein the first filter and the second filter ensure that all fluid exiting the accumulator has been filtered.
 11. The accumulator of claim 10, wherein the accumulator is a liner-style accumulator comprising an inlet opening; an outlet opening; an accumulator can; a liner disposed within and spaced from the accumulator can; one or more passageways adapted to allow the separated gaseous refrigerant to flow to a gap between the liner and the can; an oil return hole in the liner; and an outlet passage positioned down steam from the oil return hole, and the outlet passage being positioned down stream from the gap, wherein the outlet passage communicates with the outlet opening.
 12. The accumulator of claim 11 wherein the second filter is adapted to filter all of the fluid passing through the oil return hole and wherein the first filter is positioned in or near the one or more passageways, the first filter being adapted to filter all gaseous refrigerant flowing through the one or more passageways.
 13. The accumulator of claim 11, wherein the second filter is adapted to filter all of the fluid passing through the oil return hole, and the first filter comprises one or more passageway filters, wherein each one of the one or more passageways has a corresponding passageway filter, and each one of the one or more passageway filters is positioned in or near the corresponding one of the one or more passageways.
 14. The accumulator of claim 11 wherein the second filter is adapted to filter all of the fluid passing through the oil return hole, and wherein the first filter is positioned in the gap between the liner and the can, the first filter being adapted to filter all of the separated gaseous refrigerant flowing through the gap.
 15. The accumulator of claim 11 wherein the second filter is adapted to filter all of the fluid passing through the oil return hole, and wherein the first filter is positioned in a space between a deflector and the can, the first filter being adapted to filter all of the separated gaseous refrigerant flowing through the space.
 16. The accumulator of claim 10, wherein the accumulator comprises an inlet opening; an outlet opening; an outlet tube communicating with the outlet opening; and a pickup tube for entraining oil with the separated gaseous refrigerant, the pickup tube comprising the second filter for filtering the oil, the pickup tube extending from or near a bottom of the accumulator, the pickup tube communicating with the outlet tube; wherein the first filter is positioned upstream from the outlet tube and is adapted to filter all of the separated gaseous refrigerant entering the outlet tube.
 17. The accumulator of claim 16, wherein the accumulator further comprises a deflector having an upper portion comprising a deflecting surface and a lower portion, the first filter extending across the lower portion of the deflector, and an opening of the outlet tube being positioned within the lower portion of the deflector downstream from the first filter.
 18. The accumulator of claim 10, wherein the accumulator is a J-tube style accumulator comprising: an accumulator can; and a J-tube disposed within the can, the J-tube comprising an inlet, an outlet and an oil return hole; wherein the first filter is adapted to filter all gaseous refrigerant entering the inlet of the J-tube and the second filter is adapted to filter all fluid passing through the oil return hole.
 19. The accumulator of claim 18 wherein the first filter is securely engaged over the J-tube inlet, the first filter comprising a filter body, a filter mesh and a solid top, the filter body being generally cylindrical, having longitudinal ribs, with the ribs supporting the filter mesh.
 20. The accumulator of claim 10, wherein the accumulator is a liner-style accumulator comprising: an inlet opening; an outlet opening; an accumulator can; a liner disposed within and spaced from the accumulator can, thereby creating a gap between the accumulator can and the liner; an oil return hole formed in the liner; and a gas flow conduit disposed within an interior of the accumulator can for directing the separated gas refrigerant to the gap; wherein the first filter is adapted to filter all of the gaseous refrigerant flowing through the gas flow conduit and the second filter is adapted to filter all of the fluid passing through the oil return hole. 